Poisonous Spiders

Tidewater Gardens

September 24, 1989|By CHRIS SARGENT

Spiders have been getting a bad rap ever since Little Miss Muffet spilled her curds and whey, so it didn't surprise me when someone brought in a spider for identification recently. What did surprise me was that it actually was a black widow, one of the two poisonous spiders in Virginia. Of all the spiders brought in for identification, usually in various stages of "stomped on," this was the first one that really was a "bad guy."

I like spiders and feel compelled to defend them because of their beneficial activities, but I'm as unwilling as the next person to share my home with potentially harmful creatures. It might be helpful to describe the two poisonous spiders that occur here, in hopes the good spiders will be spared.

The two poisonous spiders in Virginia are the black widow and the brown recluse. (Did you notice bad guys wear dark colors even in the spider world?) Spiders, which are arachnids, not insects, have only two body parts instead of three: a thorax, which includes the head, and an abdomen. You'll need this information to understand spider descriptions.

The female black widow is the one who bites, though she is not aggressive and would prefer to run for shelter unless she is defending her egg sac. She may be nearly half an inch long and is glossy black with a plump, round abdomen that has a red hourglass mark on the bottomside. The egg sac is pear-shaped, up to half an inch wide and tan in color. The spider is found in sheltered areas such as wood stacks, fallen branches and trash piles or beneath objects. She builds an irregular web that funnels down to a den she hides in.

A black widow bite is sharp and painful, and the victim should be taken to the emergency room immediately. A small consolation: The black widow got her name from her habit of eating the male after mating, not from killing people. If you're bitten by a black widow you may feel sharp pain at the bite and throughout the body, chills, vomiting, difficulty breathing and sweating. Symptoms depend on your size, health and general sensitivity.

The brown recluse spider also is rare. The body is one-quarter to one-half inch long, with an elongated abdomen rather than a rounded fat one. It's light brown, buff or grayish colored with no markings on the abdomen. However, on top of the thorax there is a darker brown marking shaped like a violin, with the larger end nearest the eyes and the handle pointing toward the abdomen.

The brown recluse is quite shy, which works out nicely since few people want to meet one. Outdoors, it is usually found in sheltered corners among loose debris. The web is made of loose, irregular strands. Indoors, it may be found in corners or behind furniture, or hidden in clothing or the sheets on the bed.

You may not notice the bite of this spider at first because it doesn't particularly hurt. A red welt will eventually develop, and the wound usually develops a crust in the center of the reddened area. The crust eventually falls off, leaving a deep depression that may not heal for months. My mother was bitten by a brown recluse several years ago and has a permanent crater in her shin about the size of a quarter. This experience was not one of the highlights of her life.

The bite of a brown recluse will not cause the same severe physical reactions as the bite of a black widow, but the bite may need a physician's attention, who may prescribe topical antibiotics.

To control these spiders, carefully remove any materials where they might hide (wear gloves), knock down any webs you find, and simply step on, sweep out or vacuum up any errant spiders found in the house. Aerosol insecticides for use in the home can be used for one-on-one combat. Outside, you can apply a band of insecticide around the perimeter of the home, using diazinon or dursban.

Sargent is a Virginia Tech Cooperative Extension agent in Newport News. Anyone desiring further gardening information can call the service at 599-8899.